The present invention relates to a visual inspection supporting apparatus which is used for an inspector to visually inspect acceptability of soldering of electronic parts mounted on a printed circuit board, and a printed circuit board inspecting apparatus, as well as a soldering inspecting method and a method of correcting an unacceptable soldered portion using the apparatuses.
In this type of apparatus called by various names, for example, a visual inspection supporting apparatus, a printed circuit board inspecting apparatus, an automatic printed circuit board inspecting apparatus, and an external appearance inspecting apparatus, light sources of the three primary colors, i.e., red (R), green (G) and blue (B) are generally used. The light sources are so arranged as to project illuminating light at different angles to a portion to be inspected. When the portion to be inspected is imaged by an imaging device and an image obtained by the imaging is displayed, inclined surfaces or flat surfaces having different angles are indicated in different colors. Consequently, color information can be also utilized for judging whether or not soldering is acceptable.
Various proposals have been made in such a direction as to automate judgment whether or not soldering is acceptable. Examples include a proposal for an illuminating method (see Japanese Patent Application Laid-Open Publication No. 4-355311) and a proposal for image processing or judging processing (Japanese Patent Application Laid-Open Publication No. 4-343046).
However, there are not many devices and proposals from the viewpoint of assisting an inspector in visual inspection. It is highly important to increase the operation (work) efficiency of the inspector and ensure more objective judgment which is not dependent on the personal difference between inspectors. Particularly, the visual inspection has the advantage that when an unacceptable soldered portion is found out, the unacceptable soldered portion can be immediately corrected. It has been desired to realize a suitable apparatus for supporting such visual inspection.
An object of the present invention is to provide a supporting apparatus for visual inspection and correction of an unacceptable portion which makes it easy for an inspector to perform work and makes it possible to improve operation (work) efficiency.
Another object of the present invention is to provide a visual inspection supporting apparatus capable of ensuring the objectivity of judgment by an inspector.
Still another object of the present invention is to provide a printed circuit board inspecting apparatus which can be developed into not only support of visual inspection but also automatic inspection.
The present invention provides a method of judging whether or not soldering on a printed circuit board is acceptable and a method of correcting a soldered portion which is judged to be unacceptable using the visual inspection supporting apparatus and the printed circuit board inspecting apparatus.
A visual inspection supporting apparatus according to the present invention comprises an illuminating device for illuminating a printed circuit board to be inspected, an imaging device for imaging an area on the board illuminated by the illuminating device and outputting an image signal representing an image obtained by the imaging, a stage which is movable relatively to the illuminating device and the imaging device in two perpendicular directions, a board supporting member supported on the stage for supporting the board to be inspected, and a mechanism for moving the stage until the board supported on the board supporting member reaches a position outside of a range in which the illuminating device and the imaging device exist.
There is generally provided a display device for displaying the image represented by the image signal outputted from the imaging device.
The visual inspection supporting apparatus is suitable for not only inspection but also correction of an unacceptable portion. Since the board supported on the stage is drawn out of the range in which the illuminating device and the imaging device exist, it is possible to correct the unacceptable portion at the position where the board is drawn out.
Preferably, the board supporting member is supported on the stage so as to be capable of being raised and lowered, and provided is a mechanism for holding the board supporting member in its obliquely raised position.
Since the unacceptable portion can be corrected on the obliquely raised board, it becomes easy for the inspector to perform correcting work.
The image obtained by the imaging before the stage is drawn out is frozen and is displayed as a still image on the display device. The inspector can search for the unacceptable portion on the board by seeing the image.
A visual inspection supporting apparatus according to the present invention comprises an illuminating device for illuminating a printed circuit board to be inspected, an imaging device for imaging an area on the board illuminated by the illuminating device and outputting an image signal representing an image obtained by the imaging, a stage which is movable relatively to the illuminating device and the imaging device in two perpendicular directions, a movable body supported on the stage movably in either one of the two directions, and a board supporting member supported on the movable body for supporting the board to be inspected.
Since the board, along with the movable body, can be drawn out even by using this apparatus, it becomes easy to perform correcting work of an unacceptable portion.
A visual inspection supporting apparatus according to the present invention comprises an illuminating device for illuminating a printed circuit board to be inspected, an imaging device for imaging an area on the board illuminated by the illuminating device and outputting an image signal representing an image obtained by the imaging, a stage which is movable relatively to the illuminating device and the imaging device in two perpendicular directions, a rotating body rotatably supported on the stage, and a board supporting member supported on the rotating body for supporting the board to be inspected.
The board can be rotated in the use of this apparatus. Consequently, the apparatus is suitable for soldering inspection and correction of a part having a lead on four perpendicular sides.
These visual inspection supporting apparatuses and the board inspecting apparatuses further comprise storage means for storing previously taught position data representing a point to be inspected on a board to be inspected and display control means for performing control so as to indicate the point to be inspected on the image displayed on the display device in accordance with the position data stored in the storage means.
Consequently, a portion to be inspected is indicated, thereby improving the operating efficiency of the inspection.
The result of the inspection is immediately entered from an input device. A portion which is judged to be unacceptable as the result of the inspection is indicated on a screen of the display device.
More preferably, a layout display indicating the position on the board of an area of the image displayed on the display device is provided. Consequently, the inspector can find an area currently inspected, and can also grasp the progress of the inspection.
In order to make up the personal difference between inspectors to ensure objectivity, a scale for expressing the length is displayed on the image displayed on the display device.
Furthermore, two lines are movably displayed on the display screen of the display device, and the spacing between the two lines is calculated and is displayed.
Additionally, a window is displayed on the display screen of the display device, and data relating to the size of a particular image in the window is displayed. More preferably, data relating to the reference size is displayed in addition to the data relating to the size of the particular image.
The other features of the present invention will become more apparent from embodiments explained hereinbelow